We report a microwave surface imaging technique using a near-field scanning microwave microscope with a tunable resonance cavity. By tuning the resonance cavity, we could demonstrate improved sensitivity and spatial resolution of the topographic image of YBa2Cu3Oy thin films on MgO substrates. By measuring the shift of resonant frequency and the change of quality factor, we obtained near-field scanning microwave images with a spatial resolution better than 4 μm at an operating frequency of f=1–1.5 GHz. The principal of operation could be explained by the perturbation theory of a coaxial resonant cavity, considering the radius of the probe tip, the sample–tip distance, and the impedance matching.

Background/Objectives: In this research, we have explored to the concept and the element of the IoT technology, and some attacking factors to the IoT security. Methods/Statistical analysis: Things and security threats and also examined the security technology and policy contents. Findings: The most important issue for security was security technology and policy on the threat of personal information leakage, and it was found that each country is aware of its importance and is making efforts to research and prepare policies. Improvements/Applications: We will look at some security technology and other supporting policies to suggest some solutions for the direction for the currently improving IoT security.

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